The present disclosure generally relates to temperature sensing and, more particularly, to temperature sensing using a shape memory polymer.
Temperature sensing devices come in myriad forms, taking advantage of numerous underlying scientific principles. For example, mercury-, alcohol- or other liquid-containing bulb thermometers rely on the principle that the volume of a liquid is directly related to its temperature. Consequently, the volume of a liquid is actually measured and converted into a corresponding temperature. Similarly, an electronic thermometer really measures electrical resistance; and pyrometers remotely sense emitted radiation (e.g., infrared radiation). Finally, temperature strips measure the molecular structure and/or optical properties (i.e., color) of the liquid crystals from which they are formed.
Despite the variety, there are limitations in existing temperature sensing devices. For example, electronic thermometers and pyrometers, while highly portable, require a power source such as a battery, which is an added expense to what may already be an expensive device. Bulb thermometers, which are the most well-known and commonly used temperature sensing devices, are falling out of favor with some because they are prone to breaking, thereby leaking potentially toxic fluids into the environment. Thermochromic liquid crystal (TLC) temperature strips are desirable because of their portability, low cost, and convenience. However, many TLC temperature strips are irreversible or designed to be used only once and then discarded. While some TLC temperature strips are reversible (i.e., can be used more than once), they may suffer from less pronounced color changes with repeated use.
Therefore, despite their suitability for their intended purposes, there nonetheless remains a need in the art for improved temperature sensing devices. It would be particularly advantageous if these systems were reversible, relatively inexpensive to both manufacture and use, highly portable, and robust enough to withstand repeated use without degrading.